You can't be sure of people's ethnicity in the UK in 2024. Especially relatively young people. Having a British name doesn't mean much. With that being said, I lean towards the girls being ethnic English but blackfishing. Heavy salon tan, black hair dye, lip fillers, Idk what the fuck was going on with their eyebrows.
Especially with them living in London, more and more (relatively) young White people are pretending to be mixed race, tans, makeup, fashion, their accent, hairstyle etc., as that's what has cultural clout. A lot of ethnically British zoomer males unfortunate enough to be in a city or large town are downlow getting perms to help pass as mixed. Especially blackfish if you're from a middle class English family but want the attention of mixed race violent criminal males. Clifford is mixed, look at the pic of his brother.